Background

Unraveling the mystery of "Charlie" had led to the discovery, both on Earth's moon and on Ganymede, the largest of the Jovian moons, of relics of a vanished race of aliens that had inhabited a planet in the position of what today is the Asteroid Belt. They became known as the "Ganymeans" on account of the latter finds. Judy-Lynn Del Rey loved aliens, took a liking to these particular ones, and wanted another book depicting them not as reconstructions from ancient relics and artifacts, but walking, talking, and real. So, in this book it turns out that they are not completely extinct after all, as the Terran scientists supposed.